Electrical switch

ABSTRACT

An electrical scanning switch including a common contact, a plurality of individual contacts, and a member rollable over the contacts to provide an electrical connection between the common contact and each of the individual contacts in succession, the member when rolling over the contacts having no propulsive force applied to it by physical contact with the member.

United States Patent Appl. No. Filed Patented Assignee Priority ELECTRICAL swr'rcn 11 Claims, 4 Drawing Figs.

U.S.C| 335/196, 200/61.52 Int. Cl. 1101b 1/16 Field Search. 335/196, 54,124, 83; 200/52, 6l.52, 166 B; 317/101 C;

[56] References Cited UNITED STATES PATENTS 2,758,195 8/1956 Ludwig 200/6 l .52 2,487,433 1 1 1949 Gardenhour 200/52 3,348,000 10/1967 Tamm 335/54 2,802,917 8/1957 Odegaard ZOO/61.52 3,031,550 8/1962 Morrison... 1 317/101 C 2,339,063 1/1944 Deakin 335/124 Primary Examiner-Harold Broome Attorneys-Curtis, Morris and Safford, William J. Keating,

William i-lintze, Frederick W. Raring, John R. Hopkins, Adrian .1. La Rue and Jay L. Seitchik ABSTRACT: An electrical scanning switch including a common contact, a plurality of individual contacts, and a member rollable over the contacts to provide an electrical connection between the common contact and each of the individual contacts in succession, the member when rolling over the contacts having no propulsive force applied to it by physical contact with the member.

ELECTRICAL SWITCH This invention relates to an electrical switchin which an electrical connection is established between a common contact and each of a plurality of individual contacts in succession. 7

Such switches are often referred to as scanning switches and are used in various forms of data processing equipment to connect aplurality of input signals to a common outputin. succession.

Known scanning switches comprise a plurality of individual contacts arranged in relatively, fixed spacedrelationship, for example in a circle, and a commoncontact which ismovable to contact each of the individual contacts in turn. Switches with manual, and switches with automatic, for example electromechanical, control of the common contact are known.

Scanning switches are often used to make and break the energizing circuits of electromagnetic relays, and in such cases it is necessary for the common contact to remain in contact with each of .the individualcontacts for a predetermined time to ensure reliable operation of the electromagnetic relay. it is known, therefore, for the common contact to be stepped from one individual contact to the next in succession by, for example, an electric steppingv motor. With some such known switches the common contact remains in contact with each individual contact until the motor receives a signal from the circuit made by the connection just established, indicating completion of the. switching operations, e.g., operation of an electromagnetic relay, occurring on making of the circuit.

However, if a scanning switch is used to control circuits including only electronic components, then the time for which the common contact is in contact with each of. the individual contacts is not normally critical, since the scanning switch is usually the slowest operating component of the complete arrangement. Thus, precisely controlled movement of the common contact is not normally required in these circumstances.

' each of the individual contacts in succession, the member when rolling over the contacts'having no propulsive force applied to it by physical contact with the member.

The member can have the form of, for example, a sphere or a right circular cylinder. The wear on the cooperating parts of such a scanning switch-is considerably less than with known scanning switches in which always the same part of a common wiping contact slides across the surface of at least each of the individual contacts of the scanning switch.

Such a switch has the further advantage that the rolling of the member over the contacts burnishes the contacts and thus ensures good electrical contact between the member and the contacts.

Preferably the common contact, the individual contacts, and the member are arranged within a closed cross section tubular housing, the common contact extending the length of the housing and the individual contacts being arranged in axially spaced relationship along the housing so that on rolling from one end of the housing to the other the member provides an electrical connection between the common contact and each of the individual contacts in succession.

The individual contacts can be provided by an arrangement of spaced parallel conductors of aprinted circuit board, and the printed circuit board can constitute one wall of the housing. With such a scanning switch one edge of the printed circuit board can extend beyond the housing so that electrical connections can be made to the conductors of the board by means of a printed circuit board edge connector. The common contact can be connected to a conductor of the printed circuit board so that all the required electrical connections to the scanning switch can be made by means of a single printed circuit board edge connector.

Preferably the only force operative from outside the housing affecting the member while it is rolling is gravity, although other forces, for example magnetic forces, can also be used to control the member, for example to control the speed of movement of the member or to prevent rebound of the member atthe end of its movement in the housing.

Since no mechanical connection to the member from outside the housing is necessary, the only connections extending through thewalls'of the housing being the electrical connections to the common and individual contacts, the housing can be hermetically sealed, possibly after it has been evacuated or filled with oil, this protecting the contacts and member from corrosion and increasing the working life of the switch.

The member can be caused to move along the housing, i.e., the switch can be operated, by merely tilting the housing, or if the housing is rigidly mounted, by means of a manually, mechanically, or electromechanically operated arrangement. As an example, the member can be struck by a striker which is moved by means of a solenoid. The solenoid can be connected for energization on making of a circuit including the switch, so that the switch is then operated.

The housing, in cross section, may be in the form of a straight, rectangular or circular tube or any other suitable configuration.

Preferably, if the member is in the form of a sphere, it rolls on two mutually'inclined surfaces only. With such an arrangement the speed of movement of the ball can be varied by changing the angle enclosed by the two surfaces.

Alternatively, one of the surfaces can be rotatable about an axis, relative to the other surface, such that the surfaces can have relative positions including positions in which the angle included by the surfaces increases from one end of the one surface to the other end of the one surface, positions in which the angle included by the surfaces decreases from the one end of the one surface to the other end of theone surface, and a position in which the angle included by the surfaces is constant.

With such a scanning switch the ball can be caused to roll, i.e., the switch can be operated, merely by rotating the one surface about the axis of rotation thereof.

Preferably the axis of rotation of theone surface intersects the plane of the one surface intermediate the ends of the one surface.

The speed of movement of the member can otherwise be dependent upon the shape'of the housing. For example, if the housing is a linear tube along which the member rolls under the force of gravity, the housing can be made longitudinally arcuate so that after the member has been caused to move the tendency for the member to accelerate is counteracted by the constantly changing slope of the housing with respect to the horizontal.

If the individual contacts are printed circuit board conductors, the common contact can also be constituted by a conductor of the printed circuit board, the common contact conductor having a plurality of spaced parallel fingers branching from it, each of the fingers being positioned adjacent but spaced from an individual contact so that the finger and the individual contact are bridged by the member as it moves across the finger and the individual contact. With such an arrangement the strip can be broken to provide a plurality of individual groups of fingers, thus enabling separate scanning of the group of individual contacts associated with the fingers of each group to be carried out. This is of particular advantage if the individual contacts of a single scanning switch are connected to a plurality of different input signal sources, each source supplying signals to a plurality of the individual contacts of the scanning switch, for example as in card reading arrangements having more than one card reader. in this case the breaking of the strip to provide groups of common contact fingers allows readout to be carried out for any card reader individually, or for any group of the card readers.

These and other objects, features and advantages of the present invention will be understood in greater detail from the following description and accompanying drawings.

FIG. 1 is a diagrammatic side elevation of the switch with part removed;

FIG. 2 is a plan view of the switch with part removed;

FIG. 3 is a section on the line Ill-III in FIG. 1; and

FIG. 4 is a partial planview showing an alternative construction for the present invention.

The switch comprises a circular cross-sectional tubular housing 1 closed at each end by an end cap 2. Extending through slots in the wall of the housing 1 are two printed circuit boards 3 and 4. The board 3 carries a plurality of spaced parallel conductors 5 constituting the individual contactsof the switch, and the inner face of the board 4 is covered with a conductive layer 6 (FIG. 3) constituting the common contact of the switch. As shown, the boards 3 and 4 diverge in the direction away from the housing 1, and enclose an angle of approximately '30. A gold-plated ball 7 is arranged between the boards 3 and 4, and is free to roll along the housing 1 in contact with only the boards 3 and 4. Thus, as the ball 7 rolls along the housing 1 it provides an electrical connection between the layer 6 (common contact) and each of the conductors 5 (individual contacts) in succession. Each end cap 2 projects into the housing I, and carries an insert 8 having a rounded free end which acts as a stop for the ball 7 to limit its movement along the housing 1.

It is preferable for the housing 1 to be evacuated and then hermetically sealed to prevent corrosion of the contacts 5 and 6, and the ball 7. Otherwise, the housing 1 can be filled with oil and then sealed, this giving the advantage of slowing the speed of rolling of the ball 7 within the housing 1. Preferably an air bubble is left in the oil such that when the housing 1 is tilted with respect to the horizontal the air bubble reaches the raised end of the housing 1 to ensure that the ball 7 leaves this end and commences to roll.

The housing 1 carries two centrally arranged circular bosses 9 with which the housing 1 is mounted in a U-section, inverted-T-shaped stand 10 so as to be tiltable about the bosses 9 with respect to the horizontal. Mounted centrally on and beneath the housing 1 is a bracket 11 which carries a pin 12 which engages in a slot at one end of a lever 13 which is pivotally mounted on a spindle 14 carried by the stand 10. The lower end of the lever 13 is pivotally connected to one end of a further lever 15, and the other end of which is pivotally connected to the plunger 16 of a solenoid 17. A spring (not shown) on the spindle 14 engages the lever 13 to urge the lower end of the lever 13, and thus the plunger 16, away from the solenoid 17. The housing I is thus normally tilted with respect to the horizontal with its end over the solenoid 17 uppermost, the ball 7 then being at the lower end of the housing 1. When the solenoid 17 is energized it attracts the plunger 16 and thus by means of the lever and 13 tilts the housing I in the other direction relative to the horizontal, i.e. with its end remote from the solenoid l7 uppermost, thus causing the ball 7 to roll along the housing 1 to effect scanning of the individual contacts 5. When the solenoid 17 is deenergized the spring returns the housing 1 to its initial position, the ball 7 again rolling the length of the housing 1 to its initial position.

For use of the switch the individual contacts 5 can be connected by means of a printed circuit board edge connector mated with the exposed edge of the board 3, and the common contact 6 can be connected in any convenient manner, possible by use of a further printed circuit board edge connector. The alternative construction mentioned earlier in the specification is set forth in FIG. 4 wherein board 4 remains stationary while board 3 is rotatable about an axis relative to board 4 such that the two boards can have relative positions including positions in which the angle included by the surfaces increases from one end to the other (left to right as seen in FIG. 4).

Board 3' has been rotated in FIG. 4 in the direction of arrow A whereby the conductive sphere 7' will be free, under the influence of gravity, to roll to the right until it assumes the posi' tion indicated at 7". The direction of rotation of the board 3' may, of course, be reversed to permit the ball to move from right to left. When the boards are parallel to one another the ball will remain stationary We claim:

1. An electrical scanning switch including two substantially planar mutually inclined surfaces, a plurality of individual contacts carried on one of the planar surfaces, a common contact carried on the other planar surface, a conductivemember supported on the inclined surfaces and rollable under the action of gravity from one end of the inclined surfaces continuously to the other end to bridge electrically the common contact and each of the individual contacts in succession, said other planar surface being uninterrupted so as to present a suitable surface for the continuous rolling of the conductive member.

2. A switch as claimed in claim 1 in which one of the planar surfaces is rotatable about a vertical axis selectively to position either end of the rotatable planar surface nearer the other planar surface, and the conductive member is a sphere rollable in a direction away from the end of the rotatable planar surface nearer the other planar surface.

3. A switch as claimed in claim 1, in which the common contact, the individual contacts, and the member are arranged within a closed cross section tubular housing, the common contact extending the length of the housing and the individual contacts being arranged in axially spaced relationship along the housing so that on rolling from one end of the housing to the other the member provides an electrical connection between the common contact and each of the individual contacts in succession.

4. A switch as claimed in claim 3, in which individual contacts are provided by an arrangement of speed parallel conductors of a printed circuit board.

5. A switch as claimed in claim 4, in which the printed circuit board constitutes one wall of the housing.

6. A switch as claimed in claim 5, in which one edge of the printed circuit board extends beyond the housing so that electrical connections can be made to the conductors of the board by means of a printed circuit board edge connector.

7. A switch as claimed in claim 6, in which the common contact is connected to a conductor of the printed circuit board so that all the required electrical connections to the scanning switch can be made by means of a single printed circuit board edge connector.

8. A switch as claimed in claim 1, in which the member is in the form of a sphere and rolls on two mutually inclined surfaces only.

9. A switch as claimed in claim 4, in which the common contact is constituted by a conductor of the printed circuit board, the common contact conductor having a plurality of spaced parallel fingers branching from it, each of the fingers being positioned adjacent but spaced from an individual contact so that the finger and the individual contact are bridged by the member as it moves across them.

10. A switch as claimed in claim 9, in which the housing is pivotally mounted on a stand for reciprocal movement relative to the stand whereby the member can be caused to roll in either direction along the housing.

11. A switch as claimed in claim 10, including a solenoid coupled to the housing by a lever system to effect the pivotal movements of the housing.

TED STATES PATENT @FFEQE e F e @RWEQATt @F @REQTW Paw-m 3,629,748 Deteci December 21, 1971 invenwfl JOHN COVETL COLLIER ET AL It is certified that error appears in the above-identified patent and that said Letters Patent are hereby correctec'i as shown below:

Ila

Claim 4, line 36, column 4, "speed" should be spaced Signed and sealed this 25th day of A il 197.2a

(SEAL) Attest:

EDWARD MoFLEI'CI-IER,JlRea ROBERT GOTTSCHALK Attestlng Officer Commissioner of Patents AMP Z884 Eate-m; Nam 3,629 ,748 fiamfi Inv an wris) JOHN covmx, COLLIER m.

1D: is eercified that water appears in the ebove identified patent and that said Lettezs Patent are hereby eelrecced as shew balm Claim 4, line 36; column 4 "x-zpeec'i should. be u spaced a Signed and sealed this 25th day of A ril 1972;.

{SELL} Affest:

EDWARD MoFLETCwlR JRo ROBERT GOTTSCHALK Attestlng Officer Commissioner of Patents 

1. An electrical scanning switch including two substantially planar mutually inclined surfaces, a plurality of individual contacts carried on one of the planar surfaces, a common contact carried on the other planar surface, a conductive member supported on the inclined surfaces and rollable under the action of gravity from one end of the inclined surfaces continuously to the other end to bridge electrically the common contact and each of the individual contacts in succession, said other planar surface being uninterrupted so as to present a suitable surface for the continuous rolling of the conductive member.
 2. A switch as claimed in claim 1 in which one of the planar surfaces is rotatable about a vertical axis selectively to position either end of the rotatable planar surface nearer the other planar surface, and the conductive member is a sphere rollable in a direction away from the end of the rotatable planar surface nearer the other planar surface.
 3. A switch as claimed in claim 1, in which the common contact, the individual contacts, and the member are arranged within a closed cross section tubular housing, the common contact extending the length of the housing and the individual contacts being arranged in axially spaced relationship along the housing so that on rolling from one end of the housing to the other the member provides an electrical connection between the common contact and each of the individual contacts in succession.
 4. A switch as claimed in claim 3, in which individual contacts are provided by an arrangement of speed parallel conductors of a printed circuit board.
 5. A switch as claimed in claim 4, in which the printed circuit board constitutes one wall of the housing.
 6. A switch as claimed in claim 5, in which one edge of the printed circuit board extends beyond the housing so that electrical connections can be made to the conductors of the board by means of a printed circuit board edge connector.
 7. A switch as claimed in claim 6, in which the common contact is connected to a conductor of the printed circuit board so that all the required electrical connections to the scanning swiTch can be made by means of a single printed circuit board edge connector.
 8. A switch as claimed in claim 1, in which the member is in the form of a sphere and rolls on two mutually inclined surfaces only.
 9. A switch as claimed in claim 4, in which the common contact is constituted by a conductor of the printed circuit board, the common contact conductor having a plurality of spaced parallel fingers branching from it, each of the fingers being positioned adjacent but spaced from an individual contact so that the finger and the individual contact are bridged by the member as it moves across them.
 10. A switch as claimed in claim 9, in which the housing is pivotally mounted on a stand for reciprocal movement relative to the stand whereby the member can be caused to roll in either direction along the housing.
 11. A switch as claimed in claim 10, including a solenoid coupled to the housing by a lever system to effect the pivotal movements of the housing. 